Qjet shutting off in gear help

[84ss]

Ok this is my first post and the second time typing it as when I tried to attach a pic it deleted my entire post. Gonna try to list things so its easier
stock internal 305 from 86 Camaro'
new vac advance HEI
all vac ports on carb plugged
air pump removed
emmisions crap pulled
feedback style qjet
30 degrees total timing right now
Detent cable for turbo 350 still in place

Car runs great under throttle or in Park. Drop into gear still running good. Drive around and then come to a stop light and rpms drop real low around 500-600 and car wants to cut out. Qjets and all carbs are still mysterious to me even after 15 years and have killed projects in the past. In park I am at around 1500-2000 rpm in gear around 900rpm. Running 93 octane fuel with Stabil ethanol treatment. The only vac line run in the car right now is from the rear manifold port and that is split between the brake booster, distributor, and carb. Please help!!! Forgot to add when I shut the car off it wants to spit and sputter and sometimes even backfires out tailpipe.

 

[art]

Basics. Make sure you have compression,fuel and spark. Get it running, and check your timing. Got a "dial back" timing light? Barrow one if you don't have, and map out your timing. Might want to get a vacuum gauge to set your initial timing. Keep us posted.

 

[Bonnewagon]

"emissions crap pulled" + electronic Q-jet = headaches. You can't half step with this stuff. Either all computer stuff must be gone, or all must be functioning. Find a non CCC Q-jet and then you need to research what specs a pre-computer 305 used and apply that to your car.

 

[84ss]

Did some research and feedback Qjets are strictly only feed info to the computer so without the computer it acts like a regular (junkie) Qjet. My timing light is inductive. I def have good compression and good spark all the way to the plug. I have switched back and forth from feedback to non feedback qjets everytime I switch a new or different problem shows. Could it be an improperly setup choke? Been working on cars 19 years and still cant figure out why a carb is so difficult all it is is a damn air valve. I mean 5 different adjustment screws? Really thats stupid

 

[pontiacgp]

I don't know where you did your research but this is copied from an article in car craft..

"The Q-jet's electronic solenoid circuit is tied directly into the primary main metering circuit and is commanded by the computer that sends out part-throttle signals based on input from a narrow-band oxygen sensor. The solenoid circuit constantly adjusts the air/fuel mixture based on these signals from the computer. The primary metering circuit still functions like an original Q-jet except that the primary metering rods now move much more rapidly to adjust the air/fuel mixture."

 

[Bonnewagon]

Exactly. CCC Q-jet is told what to do by the computer based on information fed to computer by O2 sensor, TPS, MAF, temp sensor, MAP, etc. By removing everything, and/or the computer, the carb can't know what to do. So it runs on "limp home" mode which gets you what you are seeing now. Get yourself a known good running Q-jet, or other fine brand, that you are positive is set up correctly and works well. Use that and see what happens. If she runs great, you need a carb just like that one. If not, look elsewhere for the trouble. As I said before, if you are deleting everything emissions related, you must step back to a pre-computer carb which means like a 79' Q-jet set up with 79' specs like float setting, jets, rods, for a 305 and make sure the choke is working with regard to pull-off, fast idle and curb idle. Also get those vacuum lines straightened out. The big one is for the brake booster, ported vacuum is for the EGR and distributor, and full manifold vacuum is for the choke pull-off and anything else vacuum operated.

 

[G-Body_Vet]

then come to a stop light and rpms drop real low around 500-600 and car wants to cut out.

What transmission is in the car? This sounds like symptoms of a TC solenoid not disengaging.

 

[pontiacgp]

In park I am at around 1500-2000 rpm in gear around 900rpm. Running 93 octane fuel with Stabil ethanol treatment. The only vac line run in the car right now is from the rear manifold port and that is split between the brake booster, distributor, and carb. Please help!!! Forgot to add when I shut the car off it wants to spit and sputter and sometimes even backfires out tailpipe.

it sounds like the choke isn't fully shutting off....but like bonnewagon suggested until you get a proper running carb set up properly you can't really diagnose anything.

 

[tc1959]

Re: Q Jet shutting off in gear help

In order for a feedback CCC carb to work all the sensors, vacuum controls,and ecm wiring must be in place,Including the est distributor.
If your not going to use the ECM then get a non electric Q-jet .

 

[84ss]

First thing thanks guys for all this help. Seems I have been chasing problems that I cant fix till I get a new carb. Someone asked about what trans its a th350c (lockup converter). I had gotten the feedback only info on the carb from a diff website that I wont trust anymore. Seems like the choke on this one doesnt like to close either, no matter where you adjust it. I guess my next question would be what carb should I go with since its looking like fuel injecting it will be around $2000. I am going to be dropping a 350 in this car down the road. Thinking around 350-400hp. Car already has a Chev Performance high rise alum manifold on it. Mech vs Vac secondaries on street car? I am looking for a very simple carb. If you have one for sale let me know. Also can I just put a vac cap on the EGR port? May seem strange but I hate vac lines and wires running around the engine. Less is better!